Knowledge of the nutritional requirements of stock and the values of feeds are necessary for cost effective use of supplements.

Balanced rations can reduce costs and increase profits due to improved responses to supplements.

The main supplements include energy, protein, fibre and minerals. The nutritional values of supplements and roughages are shown in Table 1 (See Table 1).

ENERGY

The energy content of feeds is highly related to digestibility. Forages low in energy and high in fibre limit feed intake and nutrients available for production. The higher the production gains and energy requirements the lower the amount of low quality feed that can be part of the diet (see Table 2).

PROTEIN

The next most limiting nutrient is protein. Low protein levels reduces production.

Inadequate protein levels cause reduced digestion of roughages and supplements, however excess protein is wasted. Protein is described as crude protein (CP), rumen degradable protein (RDP) and undegradable protein (UDP).

At least two thirds of the crude protein intake should be true protein. Non protein nitrogen (NPN) can only be effectively used in diets with adequate levels of energy and true protein. New protein concepts place emphasis on the biological quality (type and levels of amino acids) and its degradability (dgP per cent). In low energy diets (eg frosted and mature native grasses) insufficient protein is produced in the rumen and stock have been shown to respond to low degradable protein (UDP) supplements.

There is much debate on the purpose and benefits of protected or bypass protein (UDP) sources. Generally high quality balanced rations allow sufficient levels of RDP and UDP for beef cattle.

Depending on the forage, protein supplements need to consider price (cost/unit of protein), crude protein and its degradability (see Table 1 and Table 3)

FIBRE

Commonly expressed as crude fibre (CF), acid detergent fibre (ADF) and neutral detergent fibre (NDF). NDF is a measure of total insoluble fibre and ADF measures cellulose and lignin but does not include hemi-cellulose. Adequate fibre is required in high grain diets to allow efficient fermentation of carbohydrates and prevent low rumen pH (acidosis). Fibre is not ‘effective’ if it is too finely chopped or is highly indigestible.

With good quality tropical pastures and summer forage crops the lack of fibre is seldom an issue. Fibre deficiencies may occur on lush temperate pastures (eg. ryegrass/clover) particularly if high levels of grain are fed.

Low digestible forages and low accessibility (eg. stemmy, dead material) reduces intake.

INTAKE

Forage intake is determined by:

• availability and access time
• number of bites
• amount harvested at each bite

High quality forages and conserved feeds have higher feed values and intakes resulting in more effective digestion and availability of nutrients,

MINERALS

In low quality or unbalanced diets, mineral supplements that need to be considered include calcium (Ca), phosphorus (P), Sodium (Na), magnesium(Mg) and potassium (K) (Table 1).

Calcium – critical for bone and soft tissue development and replacement. Cattle can compensate for short-term shortages but long term inadequacy is detrimental to stock health and production . Excess calcium may be antagonistic to the absorption of other minerals in the diet.

Maintenance requirements are 0.45% DMI and 2.5-3.0 g/kg milk.

Phosphorus – like calcium, this is a major mineral for bone and tissue, feed utilisation and production (growth, milk and re-production). Phosphorus is an economically important mineral with stock grazing pastures. Maintenance requirements are 0.3% DMI and 0.20 g/kg milk.

Magnesium – is a key activator of numerous enzyme activities and energy utilisation. The availability of Mg in certain feeds is important when calculating supplementation. Excess intake of Mg can lead to diarrhoea in stock.

Maintenance requirements are 0.6% DMI and 0.69 g/kg milk

Sodium – a highly important mineral with stock grazing pastures in hot environments. Clinical symptoms of deficiency are rare but inadequate sodium intake reduces appetite and production. Maintenance requirements are at least 0.18% DMI and 0.6 g/kg milk.

Potassium – closely related nutritionally and chemically to sodium. Deficiencies are not common on forage diets. High grain diets in hot climates show symptom similar to sodium deficiency. Maintenance requirements are 0.8% DMI.

Sulphur – has received increased interest in recent years due to the increased feeding of corn silage and non protein nitrogen compounds. Sulphur is required for optimal rumen bacterial growth and the synthesis of amino acids and protein by rumen microbes. Excess sulphur results in abdominal pain and diarrhoea.

Maintenance requirements are 0.20% DMI and 0.6 g/kg milk

TRACE MINERALS

As the name implies (“trace”), small amounts of micro-minerals (mg/kg) are required by stock. Fed in excess, trace minerals can be toxic. The main trace minerals for beef cattle include copper and selenium in some beef growing areas.

BUFFERS

These are compounds which can prevent “off feed” situations with stock fed high grain – low roughage diets. They are particularly useful when stock first start on grain diets or there is a change in the type of grain in the ration. Buffers are a feed management tool to reduce ‘grain sickness’ and do not replace the benefits of adequate levels of high quality roughages and careful introduction of grains (Table 5).

Sodium bi-carbonate, the most common buffer is also a sodium supplement. Likewise, magnesium oxide is a buffer and mineral supplement. Limestone is an extremely poor buffer but an essential source of calcium in high grain diets. Sodium bentonite is a type of clay that can be used as a buffer. It is effectively used in combination with chemical buffers. If fed in excess (above 4-5% of the concentrate) it can lead to absorbtion of other minerals (eg. calcium) (see Table 5).

NOTE:

1. Changes in the type of grain should consider a “grain introduction” program
2. At signs of sickness reduce grain intake and recommence “introduction program” once stock have stabilised.
3. Where possible use buffers that provide the necessary minerals (see Tables 6a, 6b, 6c & 6d).

FEED BUDGETS

The following feed budget examples are based on stock requirements and feed nutritional values.

CALCULATIONS INVOLVE THREE STEPS:

Step 1 – Determine stock details ie.

• type
• liveweight
• growth
• production

Step 2 – Determine the nutritional requirements ie Tables 6a – 6d)

Step 3 – Calculate nutritional balances based on feed values (ie Table 1).

EXAMPLE 1

Calculate if a ration comprising of 60% rye/clover hay, 20 per cent barley and 20 per cent tropical pastures meets the nutritional requirements of a 450 kg cow with a 3 month old calf at foot.

Step 1 – description

• Type – cow
• Liveweight – 450 kg
• Growth – maintenance at calf 3 months

Step 2 – Using nutritional requirements (Table 6c)

• energy (MJ/day) – 85
• Maximum DMI – 10.1
• Protein required – 10 per cent

Step 3 – Using feed values

• (see Tables 1 and 7)

EXAMPLE 2

Calculate if a ration comprising of 50per cent barley, 10 per cent cottonseed meal and 40% per cent medium lucerne hay meets the requirements of a 500kg bull with an expected growth rate of 1.0kg/day.

Step 1 – Description

• Type – Bull
• Liveweight – 500 kg
• Growth – maintenance + liveweight gain of 1.0 kg/day

Step 2 – Using Nutritional Requirements (Table 6d)

• Energy (MJ) day – 108
• Maximum DMI – 10.7
• Protein required – 12 per cent

Step 3 – Using feed values

• (see Tables 1 and 8)

COSTS

The selection of supplements depends on its suitability (eg. ease of feeding and storage) quality, availability and price. Both energy and protein supplements should be purchased on a unit cent basis (ie cents/kg MJ or $/kg CP).

Tables 9 and 10 provide a guide to the cost of energy and protein (see Tables 9 & 10).

TABLES AND CHARTS

TABLE 1: NUTRITIONAL VALUES FOR COMMON FEEDS (100% DM)

FEED NAME	ME MJ/KG	DGP %	CP %	NDF %	CF %	DM %	CA G/KG	P G/KG	NA G/KG
Grains
Barley	13	73	12.0	20	6.3	89	1.0	4.0	0.2
Maize	13.5	40	9.0	9	2.6	91	0.3	3.0	0.6
Oats	11.0	83	13.5	25.5	12.0	90	0.7	3.9	0.8
Sorghum	11.5	46	10.5	10.7	4.9	89	0.4	3.0	0.2
Triticale	13.0	78	13.5	12.3	3.3	90	1.0	4.0	0.4
Wheat	13.5	78	13.0	8.3	2.6	90	0.6	4.0	0.2
Miscellaneous
W/Bran	10.5	71	18.0	47.5	12.6	89	1.4	13.0	0.4
W/Pollard	11.0	79	17.5	37.5	8.4	88	2.0	10.0	2.4
Molasses	12.5	100	5.0	–	–	75	6.0	1.0	2.2
Protein Meals
Canola	9.0	72	39	26.8	12.0	90	7.0	11.0	3.0
Copra	12.5	31	22	50.8	6.8	90	2.0	5.0	0.4
Cottonseed	11.5	54	43	28.0	13.0	91	2.0	10.0	0.6
W/ c’seed	15.6	70	25	39	18.0	93	1.5	7.0	3.1
Linseed	11.5	62	33	25	10.0	91	4.3	9.0	1.2
Lupins	13.0	78	35	24	10.5	92	1.9	5.0	0.5
Safflower	11.0	74	45	30	3.1	90	2.5	8.0	0.6
Soyabean	12.0	65	45	6.5	3.3	89	5.0	8.0	5.0
Sunflower	10.0	74	32	18	8.9	91	4.0	8.0	5.0
F./Sunflower	10.0	42	32	18	8.9	91	4.0	8.0	5.0
Tropical Pastures (late veg)
Green panic7.5	76	13	60-73	25	20	3.1	2.2	0.7
Kikuyu	8.0	77	13	55-65	24	25	2.9	2.8	0.5
Paspaulum	7.5	74	12	63-77	25	20	3.3	2.6	0.4
Rhodes	7.0	71	12	60-70	28	25	3.3	2.6	0.7
Setaria	6.5	64	10	60-70	29	28	2.5	3.0	0.6
Temperate pastures (late veg)
Clover	11.0	83	18.0	40	20	22	11.0	3.0	2.4
Ryegrass	10.0	78	16.0	60	30	26	3.6	2.0	4.0
Lucerne	9.0	85	18.0	40	22	25	13.0	2.9	1.5
Conserved feeds (medium quality)
Hays
Clover	9.5	82	16.0	40	23	88	13	2.2	1.5
Kikuyu	7.5	56	10.0	60	28	89	3	2.8	0.5
Lucerne	8.7	81	19.5	50	30	88	12	2.0	1.8
Rye/clover	9.0	78	16.0	49	24	85	8	3.0	3.0
Setaria	7.0	79	10.0	65	31	90	2	3.0	0.6
Silages
Maize	9.0	53	8.0	48	30	25	2.7	2.0	0.1
Note: Values given to feeds are averages and nutritional levels can vary widely depending on stage of harvest, storage and environment.

TABLE 2: ENERGY VALUE AND RELATIVE INTAKE OF SAMOE FORAGES

FORAGE TYPE	ENERGY VALUE (MJ/KG DM)	RELATIVE INTAKE VALUE
Good tropical pasture	8.5-9.0	0.7
Rank tropical pasture	6.5	0.5
Lucerne	9.0-10.0	0.9
Oats	9.5	0.85
Ryegrass	10.5	1.0
Ryegrass & clover	11.0	1.1
Clover	11.0	1.25
Note: Legumes have higher intakes than grasses (Source QDPI)

TABLE 3: BYPASS POTENTIAL OF SOME FEEDS

Low	Barley grain, Oat grain, Wheat grain, Ryegrass, Legumes
Medium	Peanut, Sunflower, Soyabean meal
Med/High	Cottonseed meal, Hays, Maize grain, Brewers grain
High	Fishmeal, * p veg meals
* protected veg meals by various processes (Source: Queensland University, Brisbane)

TABLE 4: COMMON SOURCES OF MINERALS

MINERAL	GOOD	POOR	MINERAL SUPPLEMENT (% DM) IN COMPOUND
Calcium (Ca) eg	Lucerne	Tropical pastures	Dicalcium phosphate (22)
	Clover	Oats grazing	Limestone (38)
	Canola meal	Most grains	Molasses
Phosphorus (P) eg	Cottonseed meal	Tropical pastures	Dicalcium phosphate (18)
	Canola meal	Corn silage	Disodium phosphate (20)
	Safflower meal	Summer crops	Diammonium Phosphate (22)
	Cereal grains	Lucerne	Bran/pollard
Magnesium (Mg) eg	Lucerne	Sorghum grain	Magnesium sulphate (15)
	Ryegrass	Oats grain	Magnesium oxide (59)
	Clover	Barley grain	Dolomite (10)
	Oats grazing	Corn grain	Bran/pollard
Sodium (Na) eg	Lucerne	Tropical pastures	Sodium chloride (38)
	Ryegrass	Corn grain	Sodium bicarbonate (27)
	Clover	Sorghum grain	Sodium sulfate (31)
	Grazing oats	Barley grain
	Bran/Pollard
	Soyabean meal
	Sunflower meal
Potassium (K) eg	Molasses	Corn grain	Potassium chloride (51)
	Kikuyu	Oat grain	Potassium sulfate (43)
	Lucerne	Barley grain
	Ryegrass	Sorghum grain
	Grazing oats
	Bran/Pollard
sulphur (S)	Molasses	Summer crops	Magnesium sulfate (13)
	Kikuyu	Bran/Pollard	Calcium sulfate (16)
	Ryegrass	Corn silage	Sodium sulfate (10)
	Lucerne
	Clover
	Barley grain
	Cottonseed meal
Note: Macro-minerals supplements particularly S, Mg and K compounds should be used with care. Minerals, if used incorrectly can lead to imbalances and toxicity.

TABLE 5: INTRODUCTION OF GRAIN AND BUFFERS

DAY	MAX. DAILY GRAIN INTAKE (KG)	MIN. DAILY FORAGE INTAKE (KG)	SODIUM BI-CARBONATE (% IN RATION)
1	0.5-1.0	3	0.5
3	1.0-1.5	3	0.5
5	1.5-2.0	3	1.0
7	2.0-2.5	3	1.5
9	2.5-3.0	3	2.0
10-15	3.5-5.0	3	2.0
16-20	60 per cent	30-35 per cent	*
* Buffers should be replaced by 2-3% mineral supplements (eg. Sodium chloride, Dicalcium phosphate, etc.)

TABLE 6: ENERGY AND PROTEIN REQUIREMENTS OF VARIOUS CLASSES OF STOCK

Table 6a: Steers and heifers (after weaning)

LIVEWEIGHT	GROWTH RATE	MAXIMUM DAILY DRY MATTER (DM) INTAKE		METABOLISABLE ENERGY (ME) REQUIREMENT	MINIMUM ME CONCENTRATION OF DIET	CRUDE PROTEIN PERCENTAGE OF DIETARY DRY MATTER
(KG)	(KG/DAY)	% OF LIVEWEIGHT	(KG)	MJ/DAY)	(MJ/KG DM)
15	0	2.9	4.3	22	5.2*	8
	0.5	2.9	4.3	37	8.7	12
	1.0	2.9	4.3	50	11.6	13
200	0	2.8	5.5	26	4.8*	8
	0.5	2.8	5.5	44	8.0	11
	1.0	2.8	5.5	59	10.7	13
300	0	2.5	7.6	35	4.6*	8
	0.5	2.5	7.6	57	7.5	10
	1.0	-2.5	7.6	76	10.0	13
400	0	2.4	9.4	45	4.8*	8
	0.5	2.4	9.4	71	7.6	9
	1.0	2.4	9.4	93	9.9	13
500	0	2.1	10.7	55	5.1*	8
	0.5	2.1	10.7	82	7.7	10
	1.0	2.1	10.7	108	10.1	12
*Cattle on these diets may not eat to full appetite, on very poor quality (Low ME values) diets. (Source ISBN 0730667596 Vic)

Table 6b: Cows dry, pregnant mature

LIVEWEIGHT	GROWTH RATE	MAXIMUM DAILY DRY MATTER (DM) INTAKE		METABOLISABLE ENERGY (ME) REQUIREMENT	MINIMUM ME CONCENTRATION OF DIET	CRUDE PROTEIN % DIETARY DRY MATTER
(KG)	(KG/DAY)	% OF LIVEWEIGHT	(KG)	(MJ/DAY)	(MJ/KG DM)
350	0	2.4	8.5	48-60	7.0	8
400	0	2.3	9.4	52-65	7.0	8
450	0	2.2	10.1	57-69	7.0	8
500	0	2.1	10.7	61-74	7.0	8
550	0	2.0	11.2	66-78	7.0	8
(Source ISBN 0730667596 Vic)

Table 6c: Cows with suckling calves up to four months old

LIVEWEIGHT	GROWTH RATE	MAXIMUM DAILY DRY MATTER INTAKE		METABOLISABLE ENERGY (ME) REQUIREMENT	MINIMUM ME CONCENTRATION OF DIET	CRUDE PROTIEN % (DM)
(KG)	(KG/DAY)	% OF LIVEWEIGHT	(KG)	(MJ/DAY)	(MJ/KG DM)
350*	0	2.4	8.5	74	8.7	10
	0.5	2.4	8.5	91	10.7	11
400*	0	2.3	9.4	80	8.5	10
	0.5	2.3	9.4	97	10.3	11
450	0	2.2	10.1	85	8.4	10
500	0	2.1	10.7	90	8.4	10
550	0	2.0	11.2	95	8.4	10
* Young cows at these weights probably need to put on some weight after calving (for example, grow at 0.5 kg/day) because they have not yet reached their adult weight. Therefore they need better feed than older cows. (Source – ISBN 0730667596 Vic.)

Table 6d: Bulls

LIVEWEIGHT	GROWTH RATE	MAXIMUM DAILY DRY MATTER (DM) INTAKE		METABOLISABLE ENERGY (ME) REQUIREMENT	MINIMUM ME CONCENTRATION OF DIET	CRUDE PROTEIN % DIETARY DRY MATTER
(KG)	(KG/DAY)	% OF LIVEWEIGHT	(KG)	(MJ/DAY)	(MJ/KG DM)
150	1.0	2.9	4.3	50	11.6	13
200	1.0	2.8	5.5	59	10.7	13
250	1.0	2.6	6.6	68	10.3	13
300	1.0	2.5	7.6	76	10.0	13
400	1.0	2.4	9.4	93	9.9	13
500	0.5	2.1	10.7	82	7.7*	11
	1.0	2.1	10.7	108	10.1	12
600	0	2.0	11.7	63	5.4*	10
	0.5	2.0	11.7	95	8.1	11
800	0	1.8	14.4	81	5.6*	10
	0.5	1.8	14.4	117	8.1	10
*Stock of these diets may have low intakes of roughage due to low ME values (Source ISBN 0730667596 Vic)

TABLE 7: CALCULATING RATION – EXAMPLE 1

FEED	RATIONCONTENT		MJ	ME SUPPLIED	PROTEIN IN FEED	PROTEIN SUPPLIED
	(%)	(KG/DM)	(ME/KG DM)	(MJ)	(%)	(%)
Rye/Clover hay	60	60 (60% x 10.1)	9.0	54 (6 x 9)	15	9.0 (60% c 15)
Barley	20	2.0 (20% x 10.1)	13	26 (2 x 13)	12	2.4 (20% x 12)
Rhodes grass	20	2.0 (20% x 10.1)	7	14 (2 x 17)	12	2.4 (20% x 12)
Total	100	10.0 kg		94 MJ		13.8%
Requirements		10.1 kg		85 MJ		10.0%
Result – Ration meets the performance required with slightly excess energy and protein indicating that the barley supplement could be reduced to 1kg/day

TABLE 8: CALCULATING RATION – EXAMPLE 2

FEED	RATION CONTENT		MJ	ME SUPPLIED	PROTEIN IN FEED	PROTEIN SUPPLIED
	(%)	(KG/DM)	(ME/KG DM	(MJ)	(%)	(%)
Barley	50	5.3 (50% x 10.7)	13	69.5 (5.35 x 13)	12	4 (50% x 12)
Cottonseed	10	1.07 (10% x 10.7)	11.5	12.3 (1.07 x 11.5)	43	4.3 (10% x 43)
Meal
Lucerne	40	4.28 (40% x 10.7)	8.7	37.2 (4.28 x 8.7)	19.5	7.8 (40% x 19.5)
Total	100%	10.7 kg		119		16.1
Requirement		10.7 kg		108		12
Result: Ration meets expected performance with slightly excess protein and energy. In this instance the cottonseed meal is additional to requirements.

TABLE 9: COMPARITIVE COST OF ENERGY SUPPLEMENTS (CENTS/MJ ME)

FEEDSTUFFS	COST/TONNE
	100	120	150	170	180	190	200	220
13.0 MJ/kg DM eg Barley	0.85	1.02	1.28	1.45	1.53	1.62	1.70	1.88
12.0 MJ/kg DM eg Oats 0.92	1.11	1.38	1.57	1.66	1.75	1.85	2.03
14.00 MJ/kg DM eg Maize	0.79	0.95	1.19	1.34	1.42	1.50	1.59	1.74
13.5 MJ/kg DM eg Wheat	0.82	0.98	1.23	1.39	1.48	1.56	1.64	1.81
10.5 MJ/kg DM eg Bran	1.05	1.26	1.58	1.79	1.90	2.00	2.11	2.32
12.5 MJ/kg DM eg Pellets	0.88	1.06	1.33	1.51	1.60	1.68	1.77	1.95
12.5 MJ/kg DM eg Molasses	1.06	1.28	1.60	–	–	–	–	–
Note: 1. Assumed that grains are 90% DM and molasses is 75% DM.
2. For comparisons the costs/tonne need to be compared on a cents/MJ ME basis

TABLE 10: COMPARITIVE COST OF PROTIEN SUPPLEMENTS ($/KG CP)

FEEDSTUFF	COST / TONNE ($)
	200	250	300	320	340	360	380	400
	$/KG CP
22% CP eg. Copra	1.73	2.16	2.59	2.76	2.94	3.12	3.29	3.43
35% CP eg. Sunflower	1.44	1.89	2.16	2.30	2.45	2.60	2.74	2.86
40% CP eg Rapeseed	1.33	1.66	1.99	2.13	2.26	2.40	2.53	2.64
45% CP eg Cottonseed	1.22	1.52	1.83	1.95	2.07	2.20	2.32	2.42
50% CP eg Soyabean	1.11	1.38	1.66	1.77	1.88	2.00	2.11	2.20
Cost 1kg DM protein meal	2.22	2.77	3.33	3.55	3.77	4.0	4.22	4.40
Note: 1. Assumed that protein meals are 90% DM
2. For comparisons the cost/tonne needs to be compared on a $/kg CP basis